Increases in computer processor speeds into the Ghz region, and increases in bandwidth capacities and transmission speeds of networking devices are providing personal computer users with the capabilities of watching live camera generated images as they are transmitted across the internet.
These advances have increased the quality of transmitted images and feasibility of video conferencing using personal computers in both the home and the office. The importance of video conferencing for quick and efficient communication in the business world places a need for effective video conference systems for the personal computer which use low cost commercial components to achieve dynamic features suited to a live conference environment.
There are many instances during a video conferencing session whereby the user is required to move from behind his or her computer in order to demonstrate or present a device, object or corporate information of some sort. To achieve such a dynamic video conferencing environment, an image tracking system which includes an image capture device such as digital camera must effectively track a user's movements. Such a system must be easily installed on the computer and comprise a light weight, low cost and easily manufacturable mechanical components for providing efficient camera movement.
U.S. Pat. No. 4,264,928 describes a video conference system which uses a servo-motor controlled mirror to project the image of a person at a conference room table onto a TV camera when he or she talks into a microphone. The invention provides a method of tracking a person when they speak into a microphone. Based on the strength of the signals received from each persons microphone, the servo-motors position the mirror to project the image of the person talking onto the TV camera. This system is limited to televising conferences where all participants are in the same room rather than providing video conferencing for participants in remote geographical locations. Furthermore, the system incorporates motors for rotating a mirror rather than rotating the inherent weight of the TV camera.
U.S. Pat. No. 5,416,513 describes a video camera for tracking an object by comparing a specific color picked from the image to a specific color stored as a reference. Based on the processed results from comparing the specific color stored as a reference and the image received from the camera, a motor rotates and tilts the camera to follow the region in which the specific color signal detected in the image is larger than in others. However, a mechanical structure for providing efficient tilt and pan movements has not been defined.
U.S. Pat. No. 5,606,368 describes a pan and tilt mounting system for providing movement for cameras and related devices. The use of a cable drive in the system eliminates the inaccuracy inherent in similar gear driven systems. The invention does not pay particular attention to the mounting position of the motors which affects the movement efficiency. The invention discusses a tilt motor for controlling tilt movement and a pan motor for controlling rotational (panning) movement, whereby the mass of the tilt motor is subject to the rotational movement provided by the pan motor. This type of “motor loading” configuration reduces the efficiency of the pan motor and increases the torque requirements.
Accordingly, there is a need for an image tracking system for video conferencing or computer based image communication applications which is capable of effectively and efficiently tracking the movements of a user, which is relatively inexpensive to manufacture and which is easily operable.